1. Field of the Invention
This invention relates to speakerphones and more specifically to speakerphones with a cellular phone connection.
2. Description of the Related Art
The telephone has long been an essential tool for communication. There are many types of telephones based on the many ways to categorize the telephone family. A telephone may use a land line, which may be an analog Plain Old Telephone Service (POTS) line, a digital service line such as an Integrated Services Digital Network (ISDN) line, or a digital interface to a PBX which will use a T1 or PRI line. A telephone may use wireless communication to connect to the telephone network and thus to another telephone. This is commonly known as a cellular phone, if it uses a cellular network to connect to the telephone network; or a satellite phone, if it connects to telephone network through a satellite. A telephone may use radio waves to connect to a base station, which in turn connects to a telephone network using land lines. This is typically known as a cordless phone.
A telephone may have a handset, which includes a microphone and an earphone. A user has to hold the handset in a hand and hold it close to his head to make a conversation with another user on the far end of the telephone network. Many telephones may have hand-free options, where a user does not have to hold a handset. One such option is a headset, which is a good option for one-on-one private conversation. Another option is typically known as speakerphone. In the speakerphone option, the voice from the far end is reproduced through a loudspeaker. The volume from this loudspeaker is typically much louder than an earphone on a handset or a headset, so that many people can hear it. The telephone also has a microphone which can receive the near end user's voice. Because the sound from the loudspeaker in a speakerphone can reach the microphone in the speakerphone, it may cause positive feedback. Thus the speakerphone has to do more processing than a regular telephone to make it operable. A speakerphone may operate in full-duplex mode with some echo cancellation. In this mode, the near user of the speakerphone can listen to the far end user talking while at the same time be talking to the other user. A speakerphone may operate in only half-duplex mode, where only one person can speak and be heard at one time. The other person cannot be heard until the first person stops speaking completely. That need for extra processing, especially in the full-duplex mode, makes speakerphones typically more complicated and more expensive than telephones without speakerphone capabilities. The ability to allow hand-free telephone conversation makes a speakerphone a nice option in some situations. The ability to allow many users to participate in a telephone conference makes a speakerphone an essential piece of equipment in many situations, such as in many businesses. There are many full-featured speakerphones installed in virtually all conference rooms in all business offices.
Because of the complexity of speakerphones, they are typically bulkier and consume more electric power. They typically sit on a conference room tables, connecting to land lines and electric power sockets. Speakerphones have not used wireless connections. This inability to use a wireless connection is limiting the use of full feature speakerphones.
There are many other situations that a speakerphone may be required, for example in a mobile office or temporary office. While it is typically difficult to access a land line and even harder to add an additional land line in the mobile office or temporary office, it is relatively cheap and easy to add a wireless connection. In many situations, to add a wireless connection is done simply by bringing a wireless telephone handset to the location. In many parts of the world where the land line telephone network is undeveloped, cellular or satellite connection may be the only economical way to gain access to a telephone network. There is a need to make speakerphone available to locations where access to land lines is difficult.
There are some attempts to address the problem. Some vendors sell accessories for some cellular phones to add the speakerphone capability to those specific cellular phones. For example, a CCM Clip n Go attachment may add speakerphone capability to Motorola Vxx series or Nokia 33xx series cellular phones. A Dock ‘N’ Talk speakerphone system may add speakerphone capability to Motorola StarTalk series cellular phones. All these accessories are low quality add-ons with very limited capabilities. They may be capable of supporting hand-free conversation, but only marginally capable to be used in a telephone conference through the cellular phone link. Therefore, there is still a need to make full featured, conference-capable speakerphones available to cellular phone users.
It is desirable to have a method and an apparatus to take advantage of the large installed base of full featured speakerphones and to make them more useful. It is desirable to bring the full featured speakerphone capabilities to locations that are not serviced by land lines.